The present invention is directed to an arrangement for mounting a sensing pin in a multicoordinate sensing head of the type which includes a casing which defines an opening through which the sensing pin extends, and means for detecting deflection of the sensing pin with respect to the housing.
A wide variety of sensing heads are known which are typically used in conjunction with multicoordinate measuring or processing machines. Thus, for example, German patent DE-PS No. 28 04 398 describes a sensing head which is bias tensioned by means of friction springs, such that the sensing arm remains in its rest position until a previously determined limit value is exceeded. In FIG. 5 of this patent there is shown a swinging bearing for a sensing head which includes annularly arranged ball bearing elements which cooperate with cylindrical bearing elements to bring about a positive angular positioning of the sensing head housing in the manner of a lenticulation.
Furthermore, in publication No. WO81/01876 of PCT application No. PCT/SU79/00134 of Dec. 26, 1979, a sensing head is shown which functions according to the resonance-contact principle. In this sensing head, a sensing pin is provided which is angularly movable with respect to a housing, and the sensing pin includes a flange which defines a rim which abuts the bottom of the sensing pin housing around the sensing pin opening. On the upper side of the flange, opposed to the free end of the sensing pin, there is mounted a piezoelectric converter which operates to set the sensing pin in vibration. On contact between the sensing pin and the workpiece, the resonant frequency of the pin changes, and this change is evaluated by a switching circuit.
German patent DE-PS No. 27 12 181 discloses a sensing head which registers the deflection of the sensing pin with tension-sensitive or pressure-sensitive elements.
British Pat. No. 1,599,758 discloses a sensing head which utilizes an elastomeric bellows to seal off the opening between the sensing pin and the sensing head housing through which the sensing pin emerges from the housing.